A viewshed designates a field of vision witnessed by onlookers. It can be forest, grassland, ocean, or desert, and represents a biotic community within a cultural context. To have a viewshed, there must be a viewer, and a reason for this spot or area to be scrutinized. Like the word landscape, viewshed implies a witness, often for aesthetic reasons, or with an eye toward conservation because of the natural beauty of the place. On the other hand, a viewshed can hide what its creator doesn’t want the eye to see: for example, clearcuts in old-growth forests are often obscured by a viewshed of trees that mask the devastation behind.

Gretel Ehrlich